NCJ Number
112419
Journal
Discover Volume: 9 Issue: 6 Dated: (June 1988) Pages: 44-52
Date Published
1988
Length
9 pages
Annotation
Deoxyribonucleic acid (DNA) fingerprinting, developed and first used in a rape case in England, is providing a powerful new tool for forensic identification.
Abstract
The technique relies on the unique variations in DNA patterns and can be done on any type of cell, including those from blood, hair, skin, and semen samples. In the technique, DNA-containing cells are treated to release strands of DNA that are broken into fragments by restriction enzymes. Electrophoresis is used to align fragments by size on a sheet of gel. The resulting pattern of fragments is transferred to a nylon sheet and exposed to radioactively tagged probes. The nylon sheet is placed against x-ray film and processed, revealing black bands struck by the probe. The pattern of these bands constitute the DNA print. In 1987, in a Florida rape case, the judge ruled that DNA fingerprinting met the Frye standard and held it admissible as evidence. In this case, it was clearly shown that the DNA print obtained from the suspect's blood matched that of semen found in the victim. This evidence eventually led to a guilty verdict. At present, prosecutors will have to continue to convince judges of the technique's reliability and acceptance in the scientific community in a pretrial hearing before DNA evidence can be admitted. DNA evidence has brought convictions in an additional seven rape and murder trials since the initial Florida case and is being considered for use in at least another 100 cases. Illustrations.